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dccp: missing destroy of percpu counter variable while unload module

PATCH In review Wei Yongjun 4 participants 4 messages Aug 5, 2009

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Wei Yongjun

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#0 lore raw

PATCH 1/1 dccp: missing destroy of percpu counter variable while unload module

percpu counter dccp_orphan_count is init in dccp_init() by percpu_counter_init() while dccp module is loaded, but the destroy of it is missing while dccp module is unloaded. We can get the kernel WARNING about this. Reproduct by the following commands:

  $ modprobe dccp
  $ rmmod dccp
  $ modprobe dccp
WARNING: at lib/list_debug.c:26 __list_add+0x27/0x5c()
Hardware name: VMware Virtual Platform
list_add corruption. next->prev should be prev (c080c0c4), but was (null). (next
Ê7188cc).
Modules linked in: dccp(+) nfsd lockd nfs_acl auth_rpcgss exportfs sunrpc
Pid: 1956, comm: modprobe Not tainted 2.6.31-rc5 #55
Call Trace:
 [<c042f8fa>] warn_slowpath_common+0x6a/0x81
 [<c053a6cb>] ? __list_add+0x27/0x5c
 [<c042f94f>] warn_slowpath_fmt+0x29/0x2c
 [<c053a6cb>] __list_add+0x27/0x5c
 [<c053c9b3>] __percpu_counter_init+0x4d/0x5d
 [<ca9c90c7>] dccp_init+0x19/0x2ed [dccp]
 [<c0401141>] do_one_initcall+0x4f/0x111
 [<ca9c90ae>] ? dccp_init+0x0/0x2ed [dccp]
 [<c06971b5>] ? notifier_call_chain+0x26/0x48
 [<c0444943>] ? __blocking_notifier_call_chain+0x45/0x51
 [<c04516f7>] sys_init_module+0xac/0x1bd
 [<c04028e4>] sysenter_do_call+0x12/0x22
Signed-off-by Wei Yongjun <[email protected]>
---
 net/dccp/proto.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
net/dccp/proto.c +1 -0
index 3281013..1bca920 100644
@@ -1159,6 +1159,7 @@ static void __exit dccp_fini(void)
 	kmem_cache_destroy(dccp_hashinfo.bind_bucket_cachep);
 	dccp_ackvec_exit();
 	dccp_sysctl_exit();
+	percpu_counter_destroy(&dccp_orphan_count);
 }
 
 module_init(dccp_init);
Signature · 1 line
1.6.2.2
Acked-by on v1 1/1
#1 lore raw

Wei Yongjun a ¨¦crit :

Quoted 40 lines

percpu counter dccp_orphan_count is init in dccp_init() by percpu_counter_init() while dccp module is loaded, but the destroy of it is missing while dccp module is unloaded. We can get the kernel WARNING about this. Reproduct by the following commands:

  $ modprobe dccp
  $ rmmod dccp
  $ modprobe dccp
WARNING: at lib/list_debug.c:26 __list_add+0x27/0x5c()
Hardware name: VMware Virtual Platform
list_add corruption. next->prev should be prev (c080c0c4), but was (null). (next
Ê7188cc).
Modules linked in: dccp(+) nfsd lockd nfs_acl auth_rpcgss exportfs sunrpc
Pid: 1956, comm: modprobe Not tainted 2.6.31-rc5 #55
Call Trace:
 [<c042f8fa>] warn_slowpath_common+0x6a/0x81
 [<c053a6cb>] ? __list_add+0x27/0x5c
 [<c042f94f>] warn_slowpath_fmt+0x29/0x2c
 [<c053a6cb>] __list_add+0x27/0x5c
 [<c053c9b3>] __percpu_counter_init+0x4d/0x5d
 [<ca9c90c7>] dccp_init+0x19/0x2ed [dccp]
 [<c0401141>] do_one_initcall+0x4f/0x111
 [<ca9c90ae>] ? dccp_init+0x0/0x2ed [dccp]
 [<c06971b5>] ? notifier_call_chain+0x26/0x48
 [<c0444943>] ? __blocking_notifier_call_chain+0x45/0x51
 [<c04516f7>] sys_init_module+0xac/0x1bd
 [<c04028e4>] sysenter_do_call+0x12/0x22
Signed-off-by Wei Yongjun <[email protected]>
---
 net/dccp/proto.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
net/dccp/proto.c +0 -0
index 3281013..1bca920 100644

net/dccp/proto.c static void __exit dccp_fini(void) · line 1165

Quoted 7 lines
net/dccp/proto.c +1 -0
@@ -1159,6 +1159,7 @@ static void __exit dccp_fini(void)
 	kmem_cache_destroy(dccp_hashinfo.bind_bucket_cachep);
 	dccp_ackvec_exit();
 	dccp_sysctl_exit();
+	percpu_counter_destroy(&dccp_orphan_count);
 }
 
 module_init(dccp_init);
Acked-by Eric Dumazet <[email protected]>

This was added by commit dd24c001 (net: Use a percpu_counter for orphan_count) (Tue Nov 25 21:17:14 2008), so this could be a stable candidate (2.6.29 & 2.6.30)

Thanks Wei

#3 lore raw
In reply to Eric Dumazet
| > WARNING: at lib/list_debug.c:26 __list_add+0x27/0x5c()
| > Hardware name: VMware Virtual Platform
| > list_add corruption. next->prev should be prev (c080c0c4), but was (null). (next
| > �7188cc).
| > Modules linked in: dccp(+) nfsd lockd nfs_acl auth_rpcgss exportfs sunrpc
| > Pid: 1956, comm: modprobe Not tainted 2.6.31-rc5 #55
| > Call Trace:
| >  [<c042f8fa>] warn_slowpath_common+0x6a/0x81
| >  [<c053a6cb>] ? __list_add+0x27/0x5c
| >  [<c042f94f>] warn_slowpath_fmt+0x29/0x2c
| >  [<c053a6cb>] __list_add+0x27/0x5c
| >  [<c053c9b3>] __percpu_counter_init+0x4d/0x5d
| >  [<ca9c90c7>] dccp_init+0x19/0x2ed [dccp]
| >  [<c0401141>] do_one_initcall+0x4f/0x111
| >  [<ca9c90ae>] ? dccp_init+0x0/0x2ed [dccp]
| >  [<c06971b5>] ? notifier_call_chain+0x26/0x48
| >  [<c0444943>] ? __blocking_notifier_call_chain+0x45/0x51
| >  [<c04516f7>] sys_init_module+0xac/0x1bd
| >  [<c04028e4>] sysenter_do_call+0x12/0x22
| > 
| > Signed-off-by: Wei Yongjun <[email protected]>
| > ---

Thanks a lot -- I have added this to the test-tree (which is still 2.6.31-rc1), until the patch is in net-2.6,

http://eden-feed.erg.abdn.ac.uk/cgi-bin/gitweb.cgi?p�cp_exp.git;a=shortlog;h�cp
git://eden-feed.erg.abdn.ac.uk/dccp_exp [subtree dccp]

I am wondering whether there is a relationship with
http://bugzilla.kernel.org/show_bug.cgi?id692

and am cc:ing Alex Dubov, who reported it.
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